Fibers of a terephthalate/ethylene glycol polyester containing less than 0.5 percent by weight of phosphorus incorporated therein by phosphonic acid ester linkages



United States Patent 8 Claims. Cl. 260-75) ABSTRACT OF THE DISCLOSUREReadily dyeable fibers and filaments of a thermostable polyestercontaining 0.05 to 0.5 percent by weight of phosphorus incorporatedthereinto by phosphonic acid linkages and prepared by condensing (A)isophthalic and/or terephthalic acids or their esters with (B) ethyleneglycol and (C) a phosponic acid ester R RiOll ORz A or a polymericproduct obtained by heating a phosphonic acid di(}8-chloroethyl) ester.

The present application is a continuation-in-part of our applicationSer. No. 204,044, filed June 21, 1962, now abandoned.

The present invention relates to fibers, filaments and the like formedof polyesters. More generally it relates to fibers, filaments and thelike formed of modified, thermostable, phosphorus-containing polyesterswhich can readily be dyed. The term fibers, filaments and the like usedthroughout the specification shall mean all kinds of textile materialssuch as staple fibers, filaments, threads, yarns, tows, ropes, cords,cables and so on.

The high-melting polyesters, among them polyethylene terephthalate, donot possess, in the polymer molecule, special groups by which a fixationof dyestufi's is brought about. It is therefore difficult to dye thefibers and filaments prepared from these polyesters. The fibers andfilaments prepared from polyesters are on the one hand difficult to dyeas has just been mentioned and tend to pill whereas on the other handthey have excellent properties. In British patent specification No.856,917 phosphorus-containing polyesters have been described in whichphosphonic acid groups are present in dicarboxylic acids or glycols.These substituents improve the dyeability of the polyesters. However,dicarboxylic acids or glycols which are substituted by the phosphonicacid group and which have to be incorporated with the polyesters bycondensation are difficultly accessible. In this case the phosphonicacid groups do not take part in the polycondensation. From the works ofV. V. Korshak (Journal of Polymer Science, XXXI, 319 (1958)) purephosphonic acid polyglycol esters and phosphonic acid polydiphenolesters are known. However, these esters are highly viscous oils orlow-melting substances which cannot be used for the manufacture offibers and filaments. There are also known organophosphorus polyesterswhich are derived from phosphinic oxide and in which the phosphorus isdirectly bound.

In Canadian patent specification No. 601,310 polyice phosphonic acidesters modified by polycarboxylic acids, for example terephthalic acid,are described. In these polyphosphonates the phosphonate radicals arereplaced by carboxylic acid radicals and in some cases products can beprepared containing as little as about 5% of phosphonic acid, calculatedon the sum of carboxylic acids. These mixed polyesters of phosphonicacids and carboxylic acids are resinous products which, even whencontaining only 1% by weight of phosphorus, possess self-extinguishingproperties. They are suitable as flame-proof additives, for theimpregnation of paper and textile materials, as adhesives, lacquers andpaints.

Now we have found new, useful fibers, filaments and the like formed of apolymeric polyester of (A) either terephthalic acid or mixtures ofterephthalic acid with up to 15 percent by weight of isophthalic acid,(B) ethylene glycol and (C) a polyphosphonic acid ester of the formulaand polyglycol phosphonic acid polycondensation products thereof,wherein R is a member selected from the group consisting of alkyl,alkenyl, aryl, aralkyl, and alkylaryl, and chloro and bromo substituentsthereof, and R and R are each selected from the group consisting ofmethyl, ethyl, propyl, isopropyl, phenyl, fl-chloro-ethyl,B-brornoethyl, 2,3-dichloro propyl, 1,3-dichloro isopropyl, 2,3-dibromopropyl, 1,3-dibromo isopropyl and benzyl, said polymeric polyestercontaining between 0.05 and 0.5 percent by weight of phosphorusincorporated therein by phosphonic acid ester linkages.

The starting materials for the preparation of the modified polyestersfor making the fibers of the invention are ethylene glycol anddicarboxylic acids.

The acids are preferably used in the form of an ester of a volatile andat most dihydric alcohol. Methyl esters and ,B-chloroethyl esters areparticularly suitable. As the acid component, terephthalic acid is usedalong or in mixtures containing up to 15 percent by weight ofisophthalic acid.

The phosphorus compounds to be added in the preparation of the polyesterare bifunctional phosphonic acid esters of the general formula or thepolycondensation products thereof. In the above formula R represents asaturated or olefinically unsaturated aliphatic or cycloaliphaticradical or an aromatic radical or the substitution products, especiallythe chloro alkyl, alkylcycloalkyl, alkenyl, aryl, alkylaryl, aralkylradical or the substitution products, especially the chloro or bromosubstitution products thereof as well as for the corresponding oxygencontaining radicals, for example benzoyl methyl, benzoyl oxymethyl,m-methoxy phenyl.

R and R may be identical or different from one another. They may stand,for example, for the methyl, ethyl, propyl, isopropyl, phenyl,fi-chloroethyl, fl-bromethyl, 2,3-dichloro propyl, 2,3-dibromo propyl,1,3-dichloro isopropyl, 1,3-dibromo isopropyl, or benzyl group or, inthe case of polyphosphonic esters, for the methylene group.

As examples of such phosphonic acid esters there may be mentioned: thedimethyl esters and diethyl esters of methyl phosphonic acid,cyclohexylmethyl phosphonic acid, benzyl phosphonic acid,alpha-naphthyl-methylphosphonic acid, p-phenyl benzyl phosphonic acid,phenyl phosphonic acid, p-methyl phenyl phosphonic acid, 2,-di-

chloromethyl phosphonic acid, p-chloromethyl benzyl phosphonic acid,p-chlorobenzyl phosphonic acid and benzoyl methyl phosphonic acid,benzyl oxymethyl phosphonic acid diethyl ester, m-methoxy phenylphosphonic acid dimethyl ester, vinyl phosphonic acid di-fi-chlorethylester, alpha-chloromethyl phosphonic acid di-B- chlorethyl ester,fl-chlorethyl phosphonic acid di-fichlorethyl ester, S-bromethylphosphonic acid di-fibromethyl ester and the corresponding polyglycolphosphonic acid esters.

These materials are prepared by a known process taught by Korshak etal., Izvest. Akad. Nauk S.S.S.R., Otdel. Khim. Nauk, 210-216 (1958),abstracted in Chem. Abstr., 12804e (1958). The process comprises heatingphosphonic acid di(fl-chloroethyl)esters of the formula to 220 -250" C.with elimination of (CH Cl) On condensation with glycols anddicarboxylic acids, the polyglycol phosphonic acid esters are cleavedand the fragments of lower molecular weight that are split off areintroduced by condensation into the polymer in the same manner asphosphonic acid esters, so that a modified polymer forms.

fi-halogen ethyl phosphonic acid esters and p-chloromethyl benzylphosphonic acid esters are particularly preferred. If it is desired toobtain a polycondensation product having a small number of chain membersit may in certain cases be advantageous to add very small quantities ofsecondary phosphonic acid esters, for example, dibenzylphosphonic acidmethyl ester.

Phosphonic acid esters of the aforesaid kind may be admixed with thereaction mixture from the beginning. It is, however, more suitable toadd them after the dicarboxylic acid esters have undergoneester-interchange with glycol, for the organo-phosphorus compounds oftencause an inhibition of the catalyst in the presence of which theinterchange of ester radicals takes place whereby the interchange of theester radicals is rendered difficult. In this case the polycondensationproceeds in known manner with the splitting off of glycol. It is,however, also possible to prepare precondensation products from thecomponents which are free from phosphorus and to react them subsequentlywith the phosphonic acid esters or polyglycol phosphonic acid esters. Bythis measure the times of polymerization can be considerably shortened.The bifunctional phosphonic acid esters may be statistically distributedall over the macromolecule as members of the chain or they may beterminal members of the chain. When a halogen alkyl phosphonic acidester is used a large portion of the halogen is split off.

In the polyesters which form the fibers, filaments and the like,according to the invention the content of phosphorus should be withinthe range of 0.05 to 0.5%. A higher content of phosphorus would lead toan embrittlement of the material which is not desirable. With regard tothe improvement of the dyeability of the fibers, filaments and the like,the content of phosphorus should not be smaller than 0.05%, in thecase'of the modified polyethylene terephthalate. In this modifiedpolyester a phosphorus content within the range of 0.1 to 0.3% isparticularly advantageous with respect to the dyeability and with a viewto obtaining a non-pilling fiber in which the other good properties ofthe non-modified polyester remain unchanged.

For the preparation of the polyesters which form the fibers, filamentsand the like, according to the invention the ordinarytransesterification and polycondensation catalysts are used, forexample, salts of calcium, magnesium and zinc, alcoholates of alkali andalkaline earth metals, titanates and antimony trioxide. If desired,pigments or dulling agents, for example, barium carbonate and titaniumdioxide, may be added in known manner in addition to oxidationinhibitors, for example, phosphorous acid or the alkyl or aryl estersthereof. The good properties of the fibers, filaments and the likeaccording to the invention are not changed by the aforesaid additives.

Fibers, filaments and the like, according to the inven tion, which havebeen prepared from the phosphorus-containing polyesters, have notendency towards pilling and have an improved affinity for dyestuffs,for example, for basic dyestuffs such as diphenyl methane dyestuffs,triphenyl methane dyestuffs, polymethine dyestuffs, indulines,safranines, thiozone dyestuffs, oxazine dyestuffs, phthaleins andxanthone dyestuffs, and also for dispersion dyestuffs such as2-hydroxy-5-methyl-4' acetamino-azobenzene,1-amino-2-methoxy-4-amino-anthraquinone, 1.4-dia-mino-2-methoxy-anthraquinone and bromo-LS-dioxy-4.8-diamino-anthraquinone. The ability of polyethlene terephthalatesmodified with B-chlorethyl phosphonic acid ester and p-chloromethylbenzyl phosphonic acid ester to be dyed with dispersion dystuffs isimproved to such an extent that the fibers, filaments and the like canexcellently be dyed even in the absence of a carrier at the boilingtemperature of the aqueous dye bath.

It is surprising that the fibers, filaments and the like according tothe invention formed of a modified polyester containing up to 0.5% byweight of phosphorus possess these advantageous properties since themodified polyesters described in Canadian patent specification N0. 601,-310 having a phosphorus content of at least 1.0% by weight do not formfibers at all.

Because of their dyeability with basic dyestuffs as well as withdispersion dyestuffs, the fibers, filaments and the like according tothe invention offer considerable advantages with respect to dyeing. Theycan, for example, be dyed simultaneously with basic dyestuffs and withdispersion dyestuffs. In this way a depth of color is obtained which istwice as great as that obtained in the same time by a dyeing in whichdyestuffs of only one of the two aforesaid classes are used. Dyestuffsof the same or similar tints may also be used in order to enablesaturated brilliant dyeings to be obtained or, in order to obtain mixedtints, dyestuffs of different tints of the aforesaid two classes may beused.

If in addition to fibers, filaments and the like formed of the modifiedpolyesters, fibers made from non-modified polyethylene terephthalate areused, for example, in fabrics, there are very interesting possibilitiesof dyeing. If such fabrics are dyed with basic dyestuffs only, thenonmodified polyethylene terephthalate fibers remain unchanged whereaswhen such fabrics are dyed with mixtures of basic dyestuffs anddispersion dyestuffs interesting two color effects can be obtained.

If fabrics of the aforesaid kind are printed new color effects canbe-obtained by combining the use of a locally fixed dyestuff with asubsequent overdyeing. Another important advantage of the fibers,filaments and the like formed of modified polyesters according to theinvention is that in order to reduce the electrostatic charge,hydrophilic substances of basic character, for example, amino alcohols,amino,sugars and amino phenols, can be fixed to the surface of themodified polyester fiber. Since these substances are bound in a verystable way to the modified fiber reactive dyestuffs, for example,dyestuffs of the vinyl sulfonic series and of the cyanuric-chlorideseries may be used for the subsequent dyeing of the fibers which havethus been prepared.

The following examples serve to illustrate the invention but they arenot intended to limit it thereto.

Example 1 500 grams of terephthalic acid dimethyl ester were subjectedfor 3 to 4 hours to an interchange of ester radicals with 406 grams ofethylene glycol in the presence of 0.115 gram of zinc acetate and 0.153gram of antimony trioxide. Within that period the temperature rose to215 C. while an active splitting off of methanol took place.

Subsequently 12 grams of B-chlorethyl phosphonic acid di-fl-chlorethylester were added. The mixture was maintained for 1 hour at a temperaturewithin the range of 200 C. to 220 C. under nitrogen. It was then heatedto 250 C. and subsequently to 275 C. while the pressure was graduallyreduced (final pressure at most 1 mm. of mercury). After 4 to 5 hours ofcolorless polycondensation product containing 0.2% of phosphorus and0.05% of chlorine and having a relative viscosity of 1.82 (determined ina solution of 1% strength at 25 C., the solvent consisting of 3 parts ofphenol and 2 parts of tetrachlororethane) was obtained.

When 2.0 grams of titanium dioxide suspended in ethylene glycol wereadded to the reaction mixture a dull polyester was obtained.

The polyester could be spun at a temperature of 270 C. Incontradistinction to polyethylene terephthalate which had not beenmodified, the filaments prepared from the polyester obtained accordingto this example, which had been drawn and fixed and possessed goodtextile properties, could be dyed deep brilliant tints with-in 1 hour at100 C. With basic dyestuffs, for example, malachite green, or withdispersion dyestuffs, for example,2-hydroxy-5-methyl-4-acetamino-azobenzene, 1-amino-2-methoxy-4-amino-anthraquinone, 1.4-diamino-2-methoxyanthraquinone andbromo-1.5-dihydroxy-4.8-diamino-anthraquinone, in an aqueous liquidcontaining 2 to 4%, calculated on the weight of the fiber, of dyestuff.The dyeings had an excellent fastness to light, washing and abrasion.Staple fibers and staple fiber yarns prepared from the filaments of thepolyesters according to this example had no tendency towards pilling.

Example 2 500 grams of a precondensation product of terephthalic aciddimethyl ester and ethylene glycol which was not yet spinable were keptfor 1 hour under nitrogen and under normal pressure at 250 C. togetherwith 13 grams of [3- chlorethly phosphonic acid di-fi-chlorethyl esterand subsequently condensation was completed within 1 hour at a finaltemperature of 278 C. and under a pressure of 1 mm. of mercury. Thecolorless polymer thus obtained had a relative viscosity of 1.86(determined as described in Example 1) and contained 0.24% ofphosphorus. It could be well spun into filaments. The textile propertiesof the spun filament were to a large extent analogous to those mentionedin Example 1.

Example 3 444 grams of terephthalic acid dimethyl ester and 360 grams ofethylene glycol were subjected to an interchange of ester radicals inthe presence of 0.135 gram of antimony trioxide and 0.102 gram of zincacetate at a rising temperature (160 C. to 225 C.). After the splittingoff of methanol was terminated, 9 grams of4-chloromethylbenzyl-phosphonic acid diethyl ester were added. The said4-chloromethyl-benZyl-phosphonic acid diethyl ester had been preparedfrom p-chloro-methyl-benzyl-chloride and triethyl phosphite which wereused in a molar ratio of 1:1, at a temperature within the range of 150C. to 160 C. while ethyl chloride was eliminated (boiling point: 157 C.to 159 C. under a pressure of 0.002 mm. of mercury). The temperature waskept for 1 hour Within the range of 200 C. to 220 C. and then increasedto 25 0 C. Condensation was terminated within 4 hours While the pressurewas reduced (final pressure 1 mm. of mercury) and the temperature wasgradually raised to 275 C. The polycondensation product, which had apale color had a relative viscosity of 1.8 and contained 0.2% ofphosphorus and less than 0.2% of chlorine. The product could well bespun to filaments at 280 C. The drawn filaments thus prepared did notpill and could be dyed deep tints under the conditions indicated inExample 1 with the dyestuffs mentioned in that example. Staple fibersprepared from these filaments had no tendency towards pilling whenprocessed into the yarns or when processed into tissues.

Example 4 500 grams of terephthalic acid dimethyl ester were subjectedto an interchange of ester radicals with 406 grams of ethylene glycol inthe presence of 0.115 gram of zinc acetate and 0.152 gram of antimonytrioxide in the manner described in Example 1. Subsequently 15 grams ofvinyl phosphonic acid di-B-chlorethyl ester were added and the clearsolution was kept for minutes under nitrogen at a temperature of 210 C.and for 30 minutes at a temperature within the range of 230 C. to 235 C.Condensation of the batch, which was heated to 250 C. was terminated bygradually reducing the pressure until it amounted to less than 1 mm. ofmercury and by heating to 276 C. A portion of the vinyl phosphonic acidester distilled off during this operation. The yellow melt solidifiedand formed a polyester which was faintly colored, which contained 0.12%of phosphorus and had a relative viscosity of 1.75 (determined asdescribed in Example 1).

The product could be spun at 270 C., to form filaments which could bedrawn and very well be dyed with basic dyestuffs and dispersiondyestuffs as described in Example 1.

Example 5 500 grams of terephthalic acid dimethyl ester were subjectedto an interchange of ester radicals with 406 grams of ethylene glycol inthe presence of 0.153 gram of antimony trioxide and 0.115 gram of zincacetate in the manner described in Example 1. After the addition of 9.5grams of alpha-naphthyl methyl phosphonic acid diethyl ester thereaction mixture was kept for 1 hour at 220 C. under nitrogen. It wasthen heated to 250 C. Condensation was continued at the same temperaturewhile the pressure was reduced until a final pressure of 1 mm. ofmercury was attained and finally the whole was heated to 275 C. After 4/2 hours the reaction was interrupted. The polyester had a slightly graycolor and had a relative viscosity of 1.75 (determined as described inExample 1). It contained 0.18% of phosphorus. The product could be spunat 270 C. to form filaments. Fibers prepared from it did not pill andhad a considerably improved ability of being dyed with basic dyestuffsand dispersion dyestuffs as have been mentioned in Example 1.

Example 6 254 grams of terephthalic acid diglycol ester were heated for2 hours at 218 C. in 32 grams of ethylene glycol with 0.05 gram ofantimony trioxide and 5 grams of polyglycol phenyl phosphonic acid esterwhich had been prepared by heating phenyl phosphonic aciddi-flchlorethyl ester for 10 hours at 250 C. (cf. Chem. Abst. 1958,12804e). After the mixture had been heated to 250 C. the pressure wasreduced within 2 hours until finally it amounted to 0.5 mm. of mercuryand the mixture was condensed for 1 /2 hours at 275 C. until the desireddegree of viscosity was attained. The colorless polymer thus obtainedhad a relative viscosity of 1.86 and contained 0.22% of phosphorus. Thephosphorus-containing polycondensation product could be spun at 275 C.and be drawn in the normal manner. The fibers thereof did not pill and,in contradistinction to filaments prepared from non-modifiedpolyethylene terephthalate, they could excellently be dyed under theconditions indicated in Example 1 with the dyestuffs mentioned in thatexample.

Example 7 444 grams of terephthalic acid dimethyl ester and 360 grams ofethylene glycol were subjected to an interchange of ester radicals inthe presence of 0.135 gram of antimony trioxide and 0.102 gram of zincacetate in the manner described in Example 1. After the addition of 5.5grams of a phosphonic acid ester, the mixture was kept under nitrogenfor 2 hours at 220 C. (The phosphonic acid ester added, the true formulaof which could not be determined, was prepared by introducing 3 mols ofepichlorhydrine drop by drop at a temperature below 30 C. into 1 mol ofphosphorous trichloride and by subsequently rearranging the tertiaryphosphate that formed into a phosphonic acid ester by heating for 5hours at 155 C. The ester (boiling point: 198 C.208 C. at 0.02-0.06 mm.)had one of the possible formulas:

Within 2 hours at 250 C. a final pressure of 1 mm. of mercurywasattained and the mixture was condensed at 275 C. for 3 hours untilthe relative viscosity was 1.75. In the reaction 1.3-dichloro-propanol-2was split off. The colorless product could well be spun to filaments at285 C. The drawn filament, too, possessed good textile properties andcould be dyed in the manner described in Example 1 with the dyestulfsmentioned in that example. When 1 mol of hydrogen chloride was split oilby means of methanolic potassium hydroxide solution from the alkyl groupof the phosphonic acid ester used, which was bound to the phosphorousatom, the properties of the phosphonic acid ester which then containedchloromethyl and vinyl groups did not change after the ester had beencondensed into polyethylene terephthalate.

Example 8 450 grams of terephthalic acid dimethyl ester, 50 grams ofisophthalic acid dimethyl ester and 409 grams of ethylene glycol weresubjected to an interchange of ester radicals within two hours at atemperature within the range of 160 C. to 210 C. in the presence of0.115 gram of zinc acetate. After the addition of 0.153 gram of antimonytrioxide and 12 grams of fi-chlorethyl-phosphonic acid di-p-chlorethylester, the clear solution was kept for 1 hour at 210 C. and subsequentlypolycondensed within 4 /2 hours while the pressure was reduced (finalpressure 0.8 mm. of mercury) and the temperature was increased (finaltemperature 275 C.). The polyester had a phosphorus content of 0.19%, arelative viscosity of 1.99 (determined as in Example 1) and a softeningpoint of 215 C.

The product could be spun at 240 C. The drawn filaments could be dyeddeep brilliant tints with basic dyestuffs and with dispersion dyestuils.

What is claimed is:

1. A fibrous product consisting essentially of a formed polyestercondensation polymer of (A) a member selected from the group consistingof terephthalic acid, esters of terephthalic acid with volatilemonohydric or dihydric alcohols, and mixtures of terephthalic acid orits said esters with up to 15 percent by weight of isophthalic acid oresters of isophthalic acid with volatile monohydric or dihydricalcohols, (B) ethylene glycol, and (C) a member from the groupconsisting of a phosphonic acid ester of the formula and a polymericproduct obtained by heating a phosphonic acid di( 3-chloroethyl) esterof the formula R ClCHzCHzO T O CIIzCHzCl to 220-250 C. with eliminationof (CH Cl) wherein R is a member selected from the group consisting ofsaturated aliphatic radicals, olefinically unsaturated aliphaticradicals, cycloaliphatic radicals, and aromatic radicals, and R and Rare each selected from the group consisting of methyl, ethyl, propyl,isopropyl, phenyl, chloroethyl, j8-br0moethyl, 2,3 dichloropropyl, 2,3dibromopropyl, 1,3 dichloroisopropyl, 1,3 dibromoisopropyl, and benzyl,said polymer of (A), (B), and (C) containing between 0.05 and 0.5percent by weight of phosphorus incorporated thereinto by phosphonicacid ester linkages.

2. A fibrous product according to claim 1 wherein said phosphonic acidester has the formula 0 O-Ri wherein R is a member selected from thegroup consisting of alkyl, alkenyl, aryl, aralkyl and alkylaryl, andchloro and bromo substituents thereof.

3. A fibrous product according to claim 1 wherein said dicarboxylic acidis terephthalic acid and wherein said ternary polyester contains between0.1 to 0.3 percent by weight of phosphorus.

4. A fibrous product according to claim 1 wherein (C) is li-chloroethylphosphonic acid di-B-chloroethyl ester.

5. A fibrous product according to claim 1 wherein (C) is4-ch10ro-rnethyl-benzyl-phosphonic diethyl ester.

6. A fibrous product according to claim 1 wherein (C) is vinylphosphonic acid di-fi-chloroethyl ester.

7. A fibrous product according to claim 1 wherein (C) is u-naphthylmethyl phosphonic acid diethylester.

8. A fibrous product according to claim 1 wherein (C) is a polymericproduct obtained by heating phenyl phosphonic acid di( 3-chloroethyl)ester.

References Cited UNITED STATES PATENTS 2,877,204 3/1959 Duhnkrack et al.260- 3,052,653 9/1962 Iannicelli 260-75 3,058,935 10/1962 Starck et al.260-75 FOREIGN PATENTS 883,754 12/ 1961 Great Britain.

601,309 7/ 1960 Canada.

601,310 7/1960 Canada.

568,816 12/1958 Belgium.

OTHER REFERENCES Pages 319-326, Journal of Polymer Science, vol. XXXI(1958); Prague Symposium Article by Korshak, QD281, p. 6-76.

WILLIAM H. SHORT, Primary Examiner.

LOUISE P. QUAST, Assistant Examiner.

